NMR Study of Ferroelectric Diglycine Nitrate

Abstract

A proton magnetic resonance study of diglycine nitrate has been carried out from room temperature down to 90°K. The second moment in poly. crystalline samples has been found to be 9.37 gauss 2 ±0.5 gauss 2 at room temperature; this increased to a value of 24.5 gauss 2 ±1.5 gauss 2 at 90°K. A more detailed study of this variation showed two transitions, one centred at about 192°K and another smaller one at about 208°K. The line shape in a single crystal has been studied for various orientations with respect to the magnetic field direction at room temperature and 90°K. The change in the line shape at one particular orientation has been studied as a function of temperature. The results are discussed in the light of a possible mechanism of ferroelectricity in this substance.